Handedness Inventory Research Articles

Language Dominance in Left-Handers: Unveiling Left Hemisphere Global Dominance With Specific Right Hemisphere Regional Dominance.

Introduction The degree to which each human brain hemisphere governs specific cognitive processes, such as language and handedness (the preference or dominance of one hand over the other), varies across individuals. Research has explored the nature of language laterality in left-handed (LH) individuals, indicating that left-hemisphere dominance for language is commonly observed across both left- and right-handed populations. Advanced imaging techniques, including functional transcranial Doppler sonography and fMRI, have revealed subtle differences in language lateralization between LH and right-handed (RH) individuals, particularly in semantic processing tasks. These findings underscore the complex relationship between handedness and language lateralization.This study investigates thespatial patterns of language lateralization in LH and RH individuals using high-resolution fMRI data and the Human Connectome Project(HCP) multimodal parcellation (MMP). Method We utilized pre-processed MRI scans from the HCPdatabase, comprising 140 healthy young adults, with 70 individuals in each of the RH and LH groups. The language task includes two contrasts: the STORY contrast, where participants listened to brief auditory stories compared to a baseline, and the STORY-MATH contrast, where participants listened to stories versus solving addition and subtraction problems.Data processing involved the HCP Pipelines and the MMPatlas was applied for analysis. The Edinburgh Handedness Inventory categorized participants as either LH or RH. For analysis, we focused on the number of brain surface elements (3D surface vertices) with positive elements (PEs) within each brain region, indicating blood-oxygen-level-dependent (BOLD) activity. The study's methodology aimed to quantify and compare PEs across the hemispheres (paired sample) and handedness groups (independent sample), providing insights into language lateralization. Statistical analysis involved Mann-Whitney U tests for differences across gender and handedness groups and robust t-tests for hemispheric dominance. Results were visualized by projecting mean and effect size values onto a 3D brain surface. Results The analysis of hemispheric mean differences in PEs revealed robust left hemisphere dominance in both the STORY and STORY-MATH contrasts among the RH group, while the LH group exhibited more balanced activity. Significant variations in PEs were observed across numerous MMP regions, with LH individuals showing pronounced asymmetry in 67 and 76 MMP regions (out of 180 regions) in the STORY and STORY-MATH contrasts, respectively, compared to 83 and 99 regions in RH individuals. Additionally, when comparing LH and RH groups, significant differences in PEs were identified within 14 MMP regions (out of 360 regions), all demonstrating significant asymmetry in LH individuals and primarily located in the right hemisphere (12 regions), notably in the inferior parietal lobule (Brodmann 39 and 40). No differences were found in the STORY-MATH contrast. Conclusion We identified hemispheric left-lateralization dominance in brain areas associated with language processing, irrespective of handedness. However, employing multimodal brain parcellation with fMRI language tasks unveiled notable differences in specific regions. Particularly striking was the heightened activity observed in certain right hemisphere regions among LH individuals.

The relationship between facial directional asymmetry, handedness, chewing side preference, and eyedness

We aimed to describe facial directional asymmetry (DA) in individuals with different manifestations of laterality. Due to the overlap between brain and face development, a relationship between the manifestation of brain laterality and DA is hypothesised. These findings could clarify the relationship between the brain and facial phenotype and help to plan facial or oral motor rehabilitation. The DA of 163 healthy individuals was assessed by two complementary 3D methods: landmark and polygonal surface analysis using colour-coded maps. Handedness was assessed using the Edinburgh Handedness Inventory, while chewing side and eye preferences were self-reported. The results showed a similar DA pattern regardless of sex and laterality (the right-sided protrusion of the forehead, nose, lips, and chin) and a slightly curved C-shape of the midline in landmark analysis. A relationship between lateralized behaviours and DA was found only in males, in females the DA pattern was more homogenous. Right-handed individuals and right-side chewers showed a protrusion of the right hemiface. Males, left-handed and left-side chewers, manifested a protrusion of the left lateral hemiface. We suggest that these specific differences in males may be due to their typically higher level of brain asymmetry. No apparent relationship was found between eyedness and DA.

Nerve conduction, latency, and its association with hand function in young men.

The median and ulnar nerves have been suggested to play a significant role in hand function; however, there are insufficient data to determine the strength of this association. This study aimed to investigate the correlation between hand function as measured with the Grooved pegboard test (GPT) and conduction velocity and latency of the median and ulnar nerves. We collected convenience samples in the College of Medicine, KSAU-HS. We used GPT to characterize hand function and performed measured nerve conduction velocity (NCV) and latency of the ulnar and median nerves of both hands. We used the Edinburgh handedness inventory (EHI) to determine hand dominance. We recruited 28 healthy medical students aged 20-29 years (mean: 21.46 ± 1.62 years). Most were right-handed (n = 25, 89.3%), with a mean EHI score of 302 ± 210. The mean GPT time was significantly faster in the dominant (65.5 ± 6.4 s) than in the non-dominant (75.0 ± 9.6 s) hand. The NCV for the ulnar nerve of the dominant hand was significantly correlated with GPT (r = -0.52, p = 0.005) while median nerve was not correlated (0.24, p = 0.21). Regression analysis and collinearity test showed that the ulnar NCV explained 20% of the variance in GPT of the dominant hand (R2 = 0.203, p = 0.016). The ulnar nerve conduction velocity, explained 20% of the variance in GPT times of the young men. Performance on this biomarker of neurological health seems to be more influenced by other factors in healthy young individuals.

Asymmetry of the Frontal Aslant Tract Depends on Handedness.

The human brain displays structural and functional disparities between its hemispheres, with such asymmetry extending to the frontal aslant tract. This plays a role in a variety of cognitive functions, including speech production, language processing, and executive functions. However, the factors influencing the laterality of the frontal aslant tract remain incompletely understood. Handedness is hypothesized to impact frontal aslant tract laterality, given its involvement in both language and motor control. In this study, we aimed to investigate the relationship between handedness and frontal aslant tract lateralization, providing insight into this aspect of brain organization. The Automated Tractography Pipeline was used to generate the frontal aslant tract for both right and left hemispheres in a cohort of 720 subjects sourced from the publicly available Human Connectome Project in Aging database. Subsequently, macrostructural and microstructural parameters of the right and left frontal aslant tract were extracted for each individual in the study population. The Edinburgh Handedness Inventory scores were used for the classification of handedness, and a comparative analysis across various handedness groups was performed. An age-related decline in both macrostructural parameters and microstructural integrity was noted within the studied population. The frontal aslant tract demonstrated a greater volume and larger diameter in male subjects compared with female participants. Additionally, a left-side laterality of the frontal aslant tract was observed within the general population. In the right-handed group, the volume (P < .001), length (P < .001), and diameter (P = .004) of the left frontal aslant tract were found to be higher than those of the right frontal aslant tract. Conversely, in the left-handed group, the volume (P = .040) and diameter (P = .032) of the left frontal aslant tract were lower than those of the right frontal aslant tract. Furthermore, in the right-handed group, the volume and diameter of the frontal aslant tract showed left-sided lateralization, while in the left-handed group, a right-sided lateralization was evident. The laterality of the frontal aslant tract appears to differ with handedness. This finding highlights the complex interaction between brain lateralization and handedness, emphasizing the importance of considering handedness as a factor in evaluating brain structure and function.

Relationship between playing-related factors and occupational balance in professional violinists.

Playing performance of musicians may affect their occupational balance. The violin is one of the riskiest string instruments for the musculoskeletal health. To show the effect of socio-demographics, playing posture, pain, and functionality on occupational balance in professional violinists in Istanbul. Forty-five violinists aged 29.1±10.6 years were included. The Personal Information Form, the Edinburgh Handedness Inventory, the Wong-Baker Faces Pain Rating Scale, the Disability of Arm, Shoulder and Hand - Sports/Musicians (DASH-SM), the Rapid Upper Limb Assessment, and the 11-item revised version of the Occupational Balance Questionnaire (OBQ11 - T) were used. Spearman correlation analysis was performed to examine the relationship between the variables and occupational balance. The only significant correlation was found between doing regular exercise and occupational balance (r = 0.539, p < 0.001) with those having an exercise habit reporting higher occupational balance scores. The mean pain score of the violinists increased from a pre-performing mean of 1.6±2.3 to a post-performance mean of 3.91±2.4. Musicians indicate that they practice physical exercise regularly. A strong methodological limitation of this study is that variables like exercise were evaluated with a self-reported survey which limited the analysis and so we hardly find any relationships between them. To the best of our knowledge, this is the first study to evaluate the relationship between playing-related factors and occupational balance in violinists. There may be other factors affecting occupational balance in violinists and also in the other musicians. Similar studies are needed in other countries also using different assessments specific to musicians.

Toward an endophenotype for ADHD: Exploring the duration mismatch negativity in drug-free children with ADHD

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent disorders in children that is considered to affect early stages of information processes. Inefficient processing of temporal information, which is a vital auditory processing skill suggests itself as a potential candidate for investigating ADHD deficits. The Research Domain Criteria (RDoC), a neuroscience-based research framework, has been introduced to study mental illness without relying on pre-established diagnostic categories. In this regard, Mismatch Negativity (MMN) has been considered an ideal electrophysiological marker for investigating ADHD deficits. This study investigates alterations in the amplitude and latency of the MMN component in response to changes in the duration and Inter-Stimulus Interval (ISI) of basic sound stimuli within an oddball task. The MMN paradigm was employed to examine duration deviations in ADHD (n = 25, 84% male, mean age: 7.3 years, SD = 2.01) compared to Control group of typically developing (TD) children (n = 25, 72% male, mean age: 7.2 years, SD = 1.92). Participants with ADHD were introduced from an accredited psychiatrist. TD children were recruited from social media and online forms. Both groups were matched in terms of gender, age and IQ. The psychological tests conducted in this study included Conners’ Parent Rating Scale (CPRS), Gilliam Autism Rating Scale|Third Edition (Gars3), Sensory profile questionnaire and Edinburgh Handedness inventory. Our findings revealed reduced MMN amplitudes in response to two blocks of duration and ISI-based deviations in ADHD children. To elaborate in greater detail, at Fz, in Duration and ISI block, respectively, the ADHD group showed an amplitude of −1.2097 ± 0.2938 and −0.8553 ± 0.4423, while the normal group showed an amplitude of −1.8325 ± 0.3689 and −2.0855 ± 0.3802. Additionally, at Cz, the ADHD group exhibited a shorter amplitude (-1.2515 ± 0.3261 and −0.9367 ± 0.3432) compared to the normal group (−2.1319 ± 0.4445 and −2.7561 ± 0.4883), in the duration and ISI blocks, respectively. Furthermore, children with ADHD display longer MMN latencies in both experimental blocks, suggesting atypical responses. To provide more detail, at Fz, the ADHD group displayed MMN latencies of 239.68 ± 5.059 and 226.88 ± 4.885 in the Duration and ISI blocks, respectively, whereas the normal group showed MMN latencies of 228.56 ± 6.584 and 213.56 ± 4.153. Similarly, at Cz, the ADHD group exhibited longer MMN latencies (234.40 ± 5.741 and 231.44 ± 5.464) compared to the normal group (227.52 ± 6.710 and 218.00 ± 5.261) in the Duration and ISI blocks, respectively. Our findings were interpreted in the context of the internal clock model, which involves the pace of an internal pacemaker regulated by dopamine (DA) levels. The convergence of MMN and auditory timing abnormalities within the RDoC framework suggests their potential as endophenotypes for ADHD, highlighting the significance of sensory processing in understanding the disorder.

Structural brain correlates of creative personality: a voxel-based morphometric study

ABSTRACT The current study explored the neuroanatomical basis of creative personality using the voxel-based morphometric (VBM) approach. The sample comprised two groups – Creative (CR) group (professional creative artists) and matched controls with no demonstrated artistic creativity (NC) with 20 participants in each group, in the age range of 20–40 years, right-handed (screened using Edinburgh Handedness Inventory) and had minimum average intelligence (IQ > 90 on Raven’s Progressive Matrices). Professional creative artists were selected using the creativity achievement questionnaire, creativity was assessed using the Wallach & Kogan test of creativity, and personality was administered using NEO-FFI. The result indicates that creative individuals have significantly higher openness to new experiences and it positively correlates with the right middle frontal gyrus. VBM analysis indicates increased gray matter volume in the inferior frontal gyrus and anterior cingulate gyrus in the CR group, pointing toward the integration of cognitive and imaginative processes that might be implicated in creative personality.

Association of auditory processing abilities and employment in young women

BackgroundThis study aimed to investigate the relationship between employment status and auditory processing abilities in women, considering the cognitive impact of work-related demands. The objective was to study the influence of employment on forward -, backward -, operation span, 2n back, and speech perception in noise (SPIN) scores.MethodsFifty-eight women aged 20 to 64 years were categorized into working and non-working groups. Auditory cognitive assessments included forward and backward digit span, auditory 2n-back, operational span, and speech perception in noise. Mental workload, listening effort, and fatigue levels were evaluated for each test using standardized scales. Handedness was assessed using the Edinburgh Handedness Inventory. Statistical analysis involved Mann–Whitney tests and effect size calculations.ResultsWorking women scored significantly higher in 2n-back task compared to non-working counterparts, emphasizing the positive impact of employment on working memory and cognitive control processes. The working women group perceptually rated greater mental load on the operational span task than non-working group, indicating the task-specific manifestation of group differences. When the tasks are easier (2n back) or difficult (operation span), employed women exhibited an advantage in auditory processing over their counterparts. ConclusionThis study reveals nuanced cognitive differences influenced by employment status in women. Working women demonstrated superior auditory processing abilities, specifically in working memory tasks, suggesting potential cognitive benefits associated with engagement in the workforce. The elevated mental workload for dual task working memory paradigms underscores the complexity of simultaneous processing and storage, highlighting cognitive challenges in specific occupational contexts.

Testing the HERA Model for Episodic Memory in a Sample of Students

The aim of this study is to test Hemispheric Encoding/Retrieval Asymmetry model – HERA for episodic memory in a sample of students. A number of 64 right-handed students participated in the study, aged between 18 and 47 years (M = 20.66, SD = 4.84), 62 females (97%). Laterality was measured with Edinburgh Handedness Inventory and only right-handed students were included (with right laterality quotient ranging between 75 and 100, M = 99.92, SD = 4.38). The experimental design was inspired by the study of Propper et al. (2013). Participants were randomly assigned in one of the five conditions. Memory stimuli consisted of a list of 36 words and clenching stimuli consisted of 5 cm diameter rubber balls. It was hypothesized that right hand clenching (left hemisphere activation) pre-encoding and left hand clenching (right hemisphere activation) pre-recall, would result in superior episodic memory. One way ANOVA and Fisher LSD post hoc test were performed. Results supported the HERA model.

Fifty Years of Handedness Research: A Neurological and Methodological Update.

Handedness, a complex human aspect that reflects the functional lateralization of the hemispheres, also interacts with the immune system. This study aimed to expand the knowledge of the lateralization of hand, foot, and eye activities in patients with immune-mediated (IM) or other (noIM) neurological diseases and to clarify the properties of the Edinburgh Handedness Inventory (EHI) in an Italian population. Three hundred thirty-four patients with IM or noIM diseases affecting the brain or spine and peripheral nervous system were interviewed about stressful events preceding the disease, subjective handedness, and familiarity for left-handedness or ambidexterity. The patients and 40 healthy subjects underwent EHI examination. In the whole group of participants, 24 items of the EHI were classified into five factors (Hand Transitive, Hand Refined, Hand Median, Foot, Eye), demonstrating good reliability and validity. Chronological age had a significant influence on hand and foot EHI factors and the laterality quotient (LQ), particularly on writing and painting. In the patient groups, EHI factors and the LQ were also predicted by age of disease onset, duration of disease, and family history of left-handedness or ambidexterity. No differences were found between patients and healthy subjects, but pencil use scored significantly lower in patients with IM diseases than in those with noIM brain diseases. These results demonstrate that the lateralization of hand and foot activities is not a fixed human aspect, but that it can change throughout life, especially for abstract and symbolic activities. Chronic neurological diseases can cause changes in handedness. This may explain why, unlike systemic immunological diseases, IM neurological diseases are not closely associated with left-handedness. In these patients, the long version of the EHI is appropriate for determining the lateralization of body activities to contextualize the neurological picture; therefore, these findings extend the Italian normative data sets.

The Italian version of Edinburgh Handedness Inventory: Translation, transcultural adaptation, and validation in healthy subjects

ABSTRACT Lateralization is a key aspect of brain architecture and handedness is its primary manifestation. The Edinburgh Handedness Inventory (EHI) and the laterality quotient (LQ) assess the direction and consistency of handedness and require translation and cross-cultural adaptation to guarantee construct validity. We developed a standardized Italian EHI version. The developed Italian version was tested on 202 Italian subjects, classified into three hand types based on their LQs: right, mixed, and left. The frequency of left-handedness in Italians and other populations was compared to previous data. LQs from the twenty- and the ten-item original inventories were also compared. We conducted a factorial analysis. Mcdonald's Omega tested internal consistency. The prevalence of left-handedness was 6.4%, consistent with prior findings in Italian samples and other EHI translations. Age was the only socio-demographic variable that significantly affected the LQ. The internal consistency of the Italian EHI was excellent. Handedness is a feature of several cognitive functions and some neuropsychological diseases; it is influenced by socio-demographic and cultural factors and the instrument used to assess it. To provide a consistent and comparable evaluation of the construct, we recommend using this validated Italian translation of the EHI.

Translation and Validation of Edinburgh Handedness Inventory in Urdu Language for Cerebral Palsy

Aim: To translate and validate EHI in Urdu language. Methods: Non-probability convenient sampling approaches used in a descriptive cross-cultural validation research design. The study also included twenty parents of children with cerebral palsy and specialists in pediatric rehabilitation. An English professor or physician completed the back translation, while two separate multilingual translators translated EHI forward into Urdu. These translators were proficient in both Urdu and English. An expert panel committee created and approved the final version of EHI in Urdu. The consent of the guardian acquired beforehand, and confidentiality ensured. The SPSS version 21 used to input and analyzes the data, and a pretest sample of 150 people used1. Result: For reliability statistics, the mean age of participants was 40.4 with standard deviation of 15.994 and Cronbach alpha of EHI questionnaire after translation was 0.943 or after testing on parents of cerebral palsy patients was 0.964 andcontent validity also showed good content validity ratio which was 0.72. Pearson correlation showed an excellent test-retest reliability and internal consistency 0.946 and after testing intraclass correlation varied from 0.523 to 0.956-show high reliability respectively. Conclusion: The Urdu version of EHI is a valid and reliable tool for Urdu speaking population of Pakistan. Keywords: Cerebral palsy, Edinburgh handedness inventory, Ghurki trust teaching hospital, Lahore College of physical therapy

Patient Outcomes After Peripheral Nerve Injury Depend on Bimanual Dexterity and Preserved Use of the Affected Hand

Background Little is known about how peripheral nerve injury affects human performance, behavior, and life. Hand use choices are important for rehabilitation after unilateral impairment, but rarely measured, and are not changed by the normal course of rehabilitation and daily life. Objective To identify the relationship between hand use (L/R choices), motor performance, and patient-centered outcomes. Methods Participants (n = 48) with unilateral peripheral nerve injury were assessed for hand use via Block Building Task, Motor Activity Log, and Edinburgh Handedness Inventory; dexterity (separately for each hand) via Nine-Hole Peg Test, Jebsen Taylor Hand Function Test, and a precision drawing task; patient-centered outcomes via surveys of disability, activity participation, and health-related quality of life; and injury-related factors including injury cause and affected nerve. Factor Analysis of Mixed Data was used to explore relationships between these variables. The data were analyzed under 2 approaches: comparing dominant hand (DH) versus non-dominant hand (NH), or affected versus unaffected hand. Results The data were best explained by 5 dimensions. Good patient outcomes were associated with NH performance, DH performance (separately and secondarily to NH performance), and preserved function and use of the affected hand; whereas poor patient outcomes were associated with preserved but unused function of the affected hand. Conclusion After unilateral peripheral nerve injury, hand function, hand usage, and patient life arise from a complex interaction of many factors. To optimize rehabilitation after unilateral impairment, new rehabilitation methods are needed to promote performance and use with the NH, as well as the injured hand.

Association between Non-Right-Handedness and Multiple Sclerosis (MS)

Background: Only two studies have examined the relationship between handedness and Multiple Sclerosis (MS). Objective: To extend previous work examining any relationships between MS and handedness. Methods: Using an online survey, self-reported MS individuals with Primary Progressive MS (PPMS) and Relapsing Remitting MS (RRMS) (N = 188) were examined. Handedness was categorized three ways using the Edinburgh Handedness Inventory (1971): Writing Hand, Handedness Direction and Handedness Degree. Results: MS Type and Writing Hand was significant such that participants who wrote with their left hand were more likely to be diagnosed with PPMS than participants who wrote with their right hand. MS Type and Handedness Direction was significant such that left-handed women were more likely to be diagnosed with PPMS than right-handed women. Conclusion: The current study suggests that there in fact, may be a relationship between MS and handedness, particularly in women.

Investigating the involvement of the left and right hemisphere in speech production and its correlation with handedness - a repetitive transcranial magnetic stimulation study.

While traditional theories suggest a link between language lateralization and handedness, recent evidence indicates more complex neural networks underlying speech processing. This study aimed to investigate the involvement of the left and right hemispheres in speech production using repetitive transcranial magnetic stimulation (rTMS). A cohort of 58 healthy volunteers with a median age of 23 (range 19-34) were included in the study. With the use of the Edinburgh Handedness Inventory (EHI), 43 individuals were determined to be right-handed, 13 left-handed, 2 mix-handed and subsequently subdivided according to handedness decile values. rTMS was applied with 2Hz frequency and 2 seconds of duration over the left and right hemispheres to trigger speech arrest while counting downwards. Overall prevalence of speech arrest was 96.6%. Twenty-four subjects developed speech arrest after stimulation exclusively over the left hemisphere (42.9%), two people exclusively over the right hemisphere (3.5%) and 30 participants bilaterally (53.6%). Notably, the right-handed exhibited speech arrest predominantly over the left hemisphere, while the left-handed showed more variability. Receiver operating characteristics analysis revealed handedness deciles as predictors of speech lateralization. Individuals with handedness values over the 2nd right decile of EHI were more likely to have speech arrest over the left hemisphere, while left-handed over the 7th left decile were more likely to show speech arrest after rTMS over the right hemisphere. This study highlights the complexity of the relationship between speech lateralization and handedness. Further research using rTMS may provide insights into the neural mechanisms underlying speech processing and enable further studies on the treatment of aphasia.

Lateralization of the Fine Motor Skills in Right - and Left-handed Men and Women

Introduction: Motor performance is an important feature that can be measured to observe the development of the central and peripheral nervous system. Fine motor skill assessed by Morische-Leistungs-Serie (MLS) was studied in normal male and female right-handers and left-handers considering familial sinistrality and writing hand. Evaluations were conducted by measuring fine motor performance through the use of a modern computerized model. Materials and Methods: Hand preference was assessed by the Edinburgh Handedness Inventory Geschwind score (GS). Fine motor skills were measured by the MLS in the computerized Vienna Test System. Results: Left-handed volunteers had a significantly higher fine motor skills in both dominant and nondominant hands compared to right-handed volunteers. Conclusions: These results suggest that the contributions of the right and left cerebral hemispheres to the motor output of the brain depend on sex and more importantly, hand preference. It was determined that left handed subjects were more skillfull than right-handed subjects when dominant hands or weak hands were compared.

The ratio of second and fourth finger lengths (2D:4D) can determine handedness

Objective: The human body exhibits both structural and functional asymmetry. One measure of this asymmetry is the ratio of 2D:4D, which is the proportion of measurements of the 2nd (2D) and 4th finger (4D). In this research, our objective is to investigate the potential association between the ratio of 2D:4D and handedness with voluntary individuals.&#x0D; Methods: A total of 312 individuals volunteered to take part in the research, where their left and right hand's 4th and 2nd finger lengths were measured using a precise digital caliper. The "Edinburgh Handedness Inventory" was used to determine hand lateralization. To determine the significance between the two independent groups, the Mann Whitney U Test was used. On the other hand, to determine the significance between the two dependent groups, the Wilcoxon Signed Rank Test was utilized.&#x0D; Results: Of the participants, 154 were male and 158 were female (age range 18-55, mean age=28.34). According to the Edinburgh Handedness Inventory, 275 individuals were right handed, 18 were left handed, and 19 were bimanual. The Mann Whitney U Test showed a significant result in the ratio of right hand 2D:4D between male and female participants who were right handed (z =-1.979, p = 0.048). Additionally, the Wilcoxon Signed Ranks Test demonstrated a difference between the right and the left hand ratio of 2D:4D for all participants which was significant (z = -2.822, p = 0.005), as well as for participants who were right handed (z = -2.850, p = 0.004).&#x0D; Conclusion: The ratio of 2D:4D finger lengths could be a significant indicator of hand preference in both male and female healthy individuals. The ratio of 2D:4D holds potential as an indicator and research tool in understanding human emotions, thoughts, and behaviors.

Executive Functions, Processing Speed, and Memory Performance: Untangling the Age-related Effects

Abstract Context: Age-related decline in memory function is a universal phenomenon. However, several factors are known to affect memory decline associated with aging. Aim: The present research aimed to study the differences between young adults and older adults in neurocognitive functions. It also aimed to examine the relative contribution of aging and executive functions to memory performance. Subjects and Methods: The sample consisted of two groups: 43 young adults and 40 older adults. Participants were selected from the community using purposive sampling. Each participant underwent screening using the Edinburgh Handedness Inventory, Modified Mini Screen, and Global Cognitive Screen. A detailed neuropsychological assessment was individually conducted using standardized measures of executive functions, processing speed, episodic memory, and semantic memory. We examined group differences between younger and older participants using the Mann Whitney U test. Additionally, we investigated the contributions of age, processing speed, and executive function to memory through stepwise multiple regression analysis. Results: Analysis of the results suggests significantly worse performance by older participants compared to younger participants on learning and memory (p&lt;.001), semantic memory (p&lt;.001), processing speed (p&lt;.001), and executive functions (p&lt;.001). Our results further indicate that age, processing speed, and executive functions were associated with better performance in learning and memory. However, age emerged as the strongest predictor, followed by processing speed and working memory. Conclusion: Our study demonstrates that aging plays the most significant role in predicting the decline of learning and memory, as well as semantic memory. However, executive functions and processing speed can differentially influence age-associated memory decline. Future studies are warranted on larger populations and more diverse age groups to better comprehend the differential roles of speed, executive functions, and aging on memory performance. We recommend developing age- and education-based normative data for neuropsychological tools specifically tailored to the Indian population.

Both direction and degree of handedness as influential factors in rumination

ABSTRACT There is contradictory evidence on the influence of handedness on depression and anxiety. However, few studies have investigated the relationship between handedness and rumination, which is robustly associated with both depression and anxiety. This study aimed to examine the influence of direction and consistency of handedness on rumination, considering four different classifications of handedness. The study sample included 406 participants (282 females) who attended an online survey and answered a demographic questionnaire, the Edinburgh Handedness Inventory, the Ruminative Response Scale, and the second edition of the Beck Depression Inventory. Considering four different classifications of handedness, a series of one-way ANOVAs was conducted to investigate any differences between the handedness groups. Besides, linear regression models were used to predict depression or rumination scores among the whole study sample, left-handers, and right-handers. Consistency of handedness predicted rumination among right-handers (but not left-handers), with a direct association between consistency and brooding/total rumination scores. Also, consistent left-handers and consistent right-handers showed higher brooding scores than inconsistent right-handers. Overall, the results supported the significant influence of both direction and consistency of handedness on individual differences in rumination and suggested consistent- and left-handedness as perpetuating factors for ruminative response style.

Exploring praxia deficits in bipolar disorder: A cross-sectional analysis of functionality and quality of life

Background/Aim: Patients with bipolar disorder often experience praxia deficits, which might impede their functionality and quality of life. This study sought to delve into praxis defects in these patients, contrasting their praxia performance with healthy controls and illuminating the interrelation between praxia performance, functionality, and quality of life. Methods: In this cross-sectional study conducted from February to July 2023, we enrolled 203 patients diagnosed with bipolar disorder 1. Participants were recruited from the Ibni Sina and Sifa Community Mental Health Centers, both of which are affiliated with the Istanbul Tuzla State Hospital. Additionally, 201 healthy controls (HC) were recruited, primarily from the friends and relatives of the hospital staff. Patients diagnosed with bipolar disorder 1, between 18 and 65 years of age, were included based on their diagnosis as determined by the Structured Clinical Interview for DSM-5 Clinical Version (SCID-5-CV). Their right-handedness was ascertained via the Edinburgh Handedness Inventory. To minimize the confounding effects of acute mood episodes on praxia deficits, patients were required to score below 5 on the Young Mania Rating Scale (YMRS) and 7 or lower on the 17-item Hamilton Depression Rating Scale (HDRS). This criterion ensured the exclusion of individuals experiencing an active mood episode. Additionally, participants needed to have been in remission for at least six months. Healthy controls, aged 18-65 and confirmed as right-handed, were included, provided they had no personal or familial history of psychiatric conditions. A detailed interview using SCID-5-CV confirmed that the healthy controls had no history or suspicion of bipolar disorder (BD) or any other psychiatric disorder and no relatives with a psychiatric disorder. All participants (203 bipolar disorder patients and 201 healthy controls) underwent evaluations using the Test for Upper Limb Apraxia (TULIA), while the bipolar cohort received the Global Functioning Assessment-Functioning (GAF-F) and the World Health Organization Quality of Life-Brief Version (WHOQOL-BREF). Statistical analyses were conducted using SPSS 22.0. Results: We identified a critical TULIA score threshold of 217, which differentiates bipolar patients from healthy individuals with a sensitivity of 79.3% and a specificity of 77.1% (area under the curve (AUC) 0.799, P&lt;0.001). TULIA scores in bipolar patients were significantly positively correlated with functionality (GAF-F; r=0.502, P&lt;0.001) and quality of life-general health (WHOQOL; r=0.389, P&lt;0.001). TULIA pantomime subscores (OR=0.92, 95% CI 0.86-0.99, P=0.022) and CPZ use of more than 250mg per day (OR=2.24, 95% CI 1.19-4.21, P=0.012) were independent predictors of impairment in functioning in bipolar patients. Conclusion: Praxia deficits in bipolar disorder patients may be intricately tied to specific clinical features that influence both their functionality and life quality. Comprehensive praxia deficit assessments can pave the way for devising tailored interventions, enhancing praxia and, by extension, the quality of life of bipolar patients.